Shutting off water in oil wells



Patented Mar. 3, 1936 n i UNITED STATES PATENT OFFICE Gulf Research & Development. Corporation, Wilmington, Del., a corporation of Delaware No Drawing. Application December 6, 1934,

. Serial No. 756,369

11 Claims. (Cl. 166-21) This invention relates to shutting off water in pared by dissolving sulfur in the butanols, in the oil wells; and it comprises a method of differenamyl alcohols, in phenol and in cresol. Comtially shutting off the flow of water intoan oil mercial cresylic acid is satisfactory. All these well penetrating oil and water formations, withliquids are of relatively high boiling point or low out substantially affecting the flow of oil into the vaporizability and hence present no diificulties in well, wherein a solution of a normally solid plastic handling and injecting into the well; All have material in a difiicultly vaporizable liquid of a limited solubility in water. The low rate of limited solubility in water is forced into the Well solution allows the liquid containing the dissolved and caused totravel through the interstices in solid to be forceda considerable distance into the water-bearing formation, whereby slow soluthe surrounding formations, while deposition of 10 tion of the liquid in water occurs with deposition the solid material is delayed. If the solid came of the solid; all as more fully hereinafter set out of solution immediately on contact of the soluforth and as claimed. p tion with water, it would be difficult to force the Water and oil often occur together in the prosolution into the well to any great distance, be-

duoing formations adjacent an oil well. They cause a filtering face would be formed at or near 15 often occur in closely contiguous parallel strata the bore wallsin the early stages of the injecting or sand layers, and in many cases both flow into operation. the well at about the same point. Satisfactory Sulfur is not the only normally solid material methods have beendeveloped for shutting off all which can be used in this way. In some cases flows into a welLas by cementingthe well with it is desirable to employ substances of greater 2 hydraulic cement or concrete, but no satisfactory solubility in oil than sulfur. For example, in method is in use for selectively shutting off the situations where some water occurs in the oil water without affecting the oil. The present insands it is desirable to use a material which is vention provides a useful process for selective readily dissolved by oil, so that any deposition water shutoff. J in the oil sands is dissolved and flushed out by 25 In the differential shutting off of the flow of the oil during well production. Naphthalene or water intothe well without permanent intercommon resins are more readily soluble in oil ference with the oil flow, it is desirable to dethan is sulfur, and can be used to advantage in posit'material forming a precipitate in the inter- 'my process in certain cases. Other useful substices of the water sands, but it is advantageous stances of this type include stearic acid, certain 30 that the deposit be made at a point as remoteas heavy salts of organic acids, etc. These subpossible from the well. This is for the reason stances are used in conjunction with an approthat material in the exposed face is readily forced priate solvent of the type described. The resultout by pressure whereas it is mot readily forced ing solutions may have densities greater or less out when occurring at a point further into the than that of Water or well brine-s. The well treat- 35 formation; the pressure differential there being ment is modified depending on whether the treatnot so great. ing solution is more or less dense than the well wa- In the present invention, this object is secured ters. When the solution employed has a density by injecting into the well and the surrounding less than, or approximately the same as that of formation a diflicultly vaporizable liquid of limited water or the well brine the well should be pumped 40 solubility in water and carrying a dissolved plastic free of water before the solution is injected. For material; that is a crystalline solid, semi-solid example, a saturated solution of stearic acid in org'ummy substance, not soluble in water. After isoamyl alcohol has a specific gravity of 0.815 the solution is deposited in the sand, the well is at 77 F. and contains 9.43 pounds stearic acid allowed to flow. The solvent is gradually taken per 100 pounds alcohol. In treating a well with 45 up by the flowing water leaving the plastic matethis solution, brine can be first removed from rial in place. A number of solutions are suitthe well by pumping it out. The solution is then able for the present purposes. One suchsolution injected. is produced by dissolving sulfur in aniline. Ani- In case it 'is desired to avoid the necessity for line is somewhat soluble in water and after the pumping out, a somewhat modified procedure can 50 solutionihas been forced outward to the desired be followed. The treating solution can be introdistance, and the well allowed to flow, the aniduced into the well on top of the brine column line slowly dissolves in the water and is removed. and pressure applied, to force first the brine and Insoluble sulfur is left in the water sands, sealing then the solution into the water formation. For

56 them. Similar treating solutions can be preexample, a solution of sulfur in aniline,containaround 100, the solution can be injected directly without removing water from the well.

I can introduce directly into a well, after preliminary bailing or swabbing, a solution of calcium'or magnesium naphthenate in cresol. Pressure is then applied to the well to force the solution into the surrounding formation, and the well is allowed to fiow. Gradual deposition of the solid matter-occurs as the cresol is slowly'dissolved out by the water flow.

In a specific embodiment of the inventiona well producing oil and water is treated to shut off the waterivithout materially influencing the flow of oil. A batch of treating solution is made up by dissolving 150 pounds sulfur in 10,000 pounds aniline, using heat to accelerate the solution. The solution has a specific gravity of 1.023. Water and oil standing in the well are pumped out. The batch of liquid is forced into the well under pressure sufficient to make it penetrate a substantial distance into the producing formations; sand in this case. After forcing in the solution as far as possible the well is permitted to flow. The flow of water gradually takes the aniline in solution, leaving the sulfur behind to plug the pores. After treatment, the flow of water into the well is found to be stopped or .materially reduced, while the .oilflow is unaffected.

In another specific embodiment of the invention, a well producing oil and water and containing a column of saline water is treated to shut off the water. In this case it is desirable to avoid the necessity of bailing or swabbing. A batch of treating solution is made up by dissolving 500 pounds calcium naphthenate in 10,000 pounds cresol, with heating. The solution has a specific gravity of 1.018. The batch of solution is pumped into the well under pressure. It floats on the column of brine in the well. The brine and the solution are forced consecutively into the producing formations under pressure, as far as pos sible; the practical limit being reached when the pump pressure rises above the range which can be conveniently provided. The well is allowed to flow. The flow of water slowly dissolves and removes the cresol, leaving the water insoluble calposited substance tends to flow slightly under infiuence of water pressure in the water formation, sealing the interstices even more effectively. Moreover the amorphous deposits are more V0- luminous than correspondingcrystalline deposits.

What I claim is:-

1. The process of retarding the flow of water from crude petroleum wells which consists in forcing into the producing formations a solution of a plastic water insoluble substance in a difilcultly vaporizable liquid which is readily soluble vin oil and sparingly soluble in water, said solution being inert to oil and not tending to form non-liquid masses therewith, then permitting the well to flow.

2. A method of differentially shutting off flow of water into an oil well having water and oil formations adjacent the well without substantially hindering the flow of oil into the well, wherein a solution of a normally solid plastic material in a difficultly vaporizable liquid of limited solubility in water is forced into the well and into the formations surrounding the well, said solution being inert to oil and not tending to form non-liquid masses therewith, and the well is allowed to flow so as to dissolve and remove the liquid, leaving the solid deposited in the water-bearing formations but not in the oilbearing formation.

3'. The matter of claim 1 wherein the plastic substance is sulfur and the liquid is aniline.

4. The matter of claim 1 wherein the plastic substance is stearic acid and the liquid is isoamyl alcohol.

5. The matter of claim 1 wherein the liquid is an organic solvent and the solid plastic material is an organic solid.

6. The matter of claim 1 wherein the solid material is soluble in oil.

'7. The matter of claim 1 wherein the density of the solution is greater than that of water.

8. The matter of claim '1 wherein the density of the solution is'less than that of water.

9. A method of differentially shutting off fiow of water into an oil 'well having water and oil formations adjacent the well without substantially affecting flow of oil into the well, wherein water and oil standing in the well are removed, a solution of a normally solid plastic material in a difiicultly vaporizable liquid of limited solubility in water is forced into the well and the producing formations adjacent the well bore, said solution being inert to oil and not tending to form non-liquid masses therewith, and the well is allowed to flow, the flow of water dissolving away the liquid, leaving the solid deposited in the water formations but not in the oil formations.

10. A method'of differentially shutting off the fiow of Water into an oil well having water and oil formations adjacent the well without substantially affecting the flow of oil into the well, the oil well containing a column of water, wherein a solution of a normally solid plastic material in a difficultly vaporizable liquid of limited solubility in Water is introduced into the well above the water column, said solution being inert to oil and not tending to formnon-liquid masses therewith. and pressure is applied to force the water and the solution into the water formation, in turn, and the well is allowed to flow so that the water gradually dissolves away the liquid from the water strata leaving the solid deposited tion comprises a naphthenate of a metallic base dissolved in cresol.

HENRY A. AMBROSE. 

